Patents by Inventor Robijn Feenstra

Robijn Feenstra has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Downhole motor and method for directional drilling of boreholes
    Patent number: 4485879
    Abstract: The invention relates to a downhole motor having a housing of which the resistance against bending in a predetermined longitudinal plane is smaller than in any other longitudinal plane. Directional drilling of boreholes is carried out by rotating the drill string simultaneously with the rotation of the drill bit driven by the downhole motor over periods preceded and followed by selected periods during which the drill string is not rotated simultaneously with the rotation of the drill bit driven by the downhole motor.
    Type: Grant
    Filed: July 28, 1983
    Date of Patent: December 4, 1984
    Assignee: Shell Oil Company
    Inventors: Anthony W. Kamp, Robijn Feenstra
  • Method and means for controlling the course of a bore hole
    Patent number: 4465147
    Abstract: The invention relates to a method and means for controlling the course of a bore hole during drilling thereof. The means comprises a down-hole motor and two eccentric stabilizers mounted on the housing of the down-hole motor near the ends thereof. Controlling the course of a bore hole that is being drilled with the down-hole motor driving the drill bit is done by successively not rotating the drill string and rotating the drill string.
    Type: Grant
    Filed: January 31, 1983
    Date of Patent: August 14, 1984
    Assignee: Shell Oil Company
    Inventors: Robijn Feenstra, Anthony W. Kamp
  • Rotary bit with jet nozzles
    Patent number: 4341273
    Abstract: A jet rotary drill bit confirming a first strainer element allowing the passage of mud carrying small-sized particles, but preventing relatively coarse particles from passing to the jet nozzles. The first strainer element is self-cleaning and the relatively coarse particles are passed on to a second strainer on which they remain trapped.
    Type: Grant
    Filed: May 28, 1981
    Date of Patent: July 27, 1982
    Assignee: Shell Oil Company
    Inventors: Bruce H. Walker, Robijn Feenstra
  • Rotary bit with ridges
    Patent number: 4116289
    Abstract: To allow the bit to drill in formations that behave plastically, while also protecting the bit against overloading when entering a relatively soft formation, ridge-shaped elements are provided having the ridges within the rotation alloy symmetric surface defined by the scraping edges of the scraping means (natural or artificial diamonds). The flanks of the elements are positioned at an acute angle to the said surface.
    Type: Grant
    Filed: September 23, 1977
    Date of Patent: September 26, 1978
    Assignee: Shell Oil Company
    Inventor: Robijn Feenstra